U.S. patent application number 11/795030 was filed with the patent office on 2010-02-18 for quaternary ammonium salt, electrolyte, electrolyte solution and electrochemical device.
Invention is credited to Yoshinobu Abe, Kazutaka Hirano, Akihiro Nabeshima, Tetsuo Nishida, Akinori Oka, Hiroaki Tokuda, Megumi Tomisaki.
Application Number | 20100038578 11/795030 |
Document ID | / |
Family ID | 36692283 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100038578 |
Kind Code |
A1 |
Nishida; Tetsuo ; et
al. |
February 18, 2010 |
Quaternary ammonium salt, electrolyte, electrolyte solution and
electrochemical device
Abstract
A quaternary ammonium salt of the formula (1), electrolytic
solution and electrochemical device using the salt ##STR00001##
wherein R.sup.1 is straight-chain or branched alkyl having 1 to 4
carbon atoms, R.sup.2 is straight-chain or branched alkyl having 1
to 3 carbon atoms, and X.sup.- is N(CN).sub.2.sup.-, SCN.sup.-,
NO.sub.3.sup.-, NCO.sup.- or NO.sub.2.sup.-.
Inventors: |
Nishida; Tetsuo; (Osaka,
JP) ; Hirano; Kazutaka; (Osaka, JP) ;
Tomisaki; Megumi; (Osaka, JP) ; Nabeshima;
Akihiro; (Tokushima, JP) ; Abe; Yoshinobu;
(Tokushima, JP) ; Tokuda; Hiroaki; (Tokushima,
JP) ; Oka; Akinori; (Tokushima, JP) |
Correspondence
Address: |
KUBOVCIK & KUBOVCIK
SUITE 1105, 1215 SOUTH CLARK STREET
ARLINGTON
VA
22202
US
|
Family ID: |
36692283 |
Appl. No.: |
11/795030 |
Filed: |
January 12, 2006 |
PCT Filed: |
January 12, 2006 |
PCT NO: |
PCT/JP06/00668 |
371 Date: |
July 11, 2007 |
Current U.S.
Class: |
252/62.2 ;
429/203; 429/337; 429/338; 429/339; 429/340; 429/341; 548/574 |
Current CPC
Class: |
H01G 11/62 20130101;
Y02E 10/542 20130101; C07D 295/08 20130101; H01M 2300/0025
20130101; H01G 9/038 20130101; Y02P 70/50 20151101; H01M 10/056
20130101; Y02E 60/10 20130101; Y02E 60/13 20130101; H01G 9/2013
20130101 |
Class at
Publication: |
252/62.2 ;
548/574; 429/203; 429/338; 429/339; 429/340; 429/341; 429/337 |
International
Class: |
H01G 9/038 20060101
H01G009/038; C07D 207/04 20060101 C07D207/04; H01M 10/00 20060101
H01M010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2005 |
JP |
5,580/2005 |
Claims
1. A quaternary ammonium salt of the formula (1) ##STR00008##
wherein R.sup.1 is straight-chain or branched alkyl having 1 to 4
carbon atoms, R.sup.2 is straight-chain or branched alkyl having 1
to 3 carbon atoms, and X.sup.- is N(CN).sub.2.sup.- or
SCN.sup.-.
2. A quaternary ammonium salt of the formula (2) ##STR00009##
wherein X.sup.- is N(CN).sub.2.sup.- or SCN.sup.-, and Me is
methyl.
3. A composition wherein the composition comprises at least the
quaternary ammonium salt of claim 1 and an organic solvent.
4. A composition according to claim 3 wherein the organic solvent
is at least one selected from among cyclic carbonic acid esters,
chain carbonic acid esters, phosphoric acid esters, cyclic ethers,
chain ethers, lactone compounds, chain esters, nitrile compounds,
amide compounds and sulfone compounds.
5. A composition according to claim 4 wherein the organic solvent
is at least one selected from among ethylene carbonate, propylene
carbonate, dimethyl carbonate, ethylmethyl carbonate,
dimethoxyethane and acetonitrile.
6. A composition according to claim 4 wherein the organic solvent
is at least one selected from among propylene carbonate and
acetonitrile.
7. An electrolyte of the formula (3) ##STR00010## wherein R.sup.1
is straight-chain or branched alkyl having 1 to 4 carbon atoms,
R.sup.2 is straight-chain or branched alkyl having 1 to 3 carbon
atoms, and X.sup.-is N(CN).sub.2.sup.- or SCN.sup.-.
8. An electrolyte of the formula (4) ##STR00011## wherein X.sup.-
is N(CN).sub.2.sup.- or SCN.sup.-, and Me is methyl.
9. An electrolytic solution wherein the solution comprises at least
the electrolyte of claim 7.
10. An electrolytic solution wherein the solution comprises at
least the electrolyte of claim 7 and an organic solvent.
11. An electrolytic solution according to claim 10 wherein the
organic solvent is at least one selected from among cyclic carbonic
acid esters, chain carbonic acid esters, phosphoric acid esters,
cyclic ethers, chain ethers, lactone compounds, chain esters,
nitrile compounds, amide compounds and sulfone compounds.
12. An electrolytic solution according to claim 11 wherein the
organic solvent is at least one selected from among ethylene
carbonate, propylene carbonate, dimethyl carbonate, ethylmethyl
carbonate, dimethoxyethane and acetonitrile.
13. An electrolytic solution according to claim 11 wherein the
organic solvent is at least one selected from among propylene
carbonate and acetonitrile.
14. An electrochemical device wherein the electrolytic solution of
claim 13 is used.
15. A process for preparing a quaternary ammonium salt of the
formula (1) ##STR00012## wherein R.sup.1 is straight-chain or
branched alkyl having 1 to 4 carbon atoms, R.sup.2 is
straight-chain or branched alkyl having 1 to 3 carbon atoms, and
X.sup.- is N(CN).sub.2.sup.- or SCN.sup.-, comprising (a) a step of
reacting an alkylpyrrolidine of the formula (5) and a compound of
the formula (6) to prepare a quaternary ammonium salt of the
formula (1a) ##STR00013## wherein R.sup.1 is straight-chain or
branched alkyl having 1 to 4 carbon atoms, ##STR00014## wherein
R.sup.2 is straight-chain or branched alkyl having 1 to 3 carbon
atoms and Y Cl, Br or I, ##STR00015## wherein R.sup.1, R.sup.2 and
Y are same as defined above, and (b) a step of reacting the
quaternary ammonium salt of the formula (1a) and a compound of the
formula (7) MX (7) wherein M is hydrogen, alkali metal atom,
alkaline earth metal atom or metal atom, and X.sup.- is
N(CN).sub.2.sup.- or SCN.sup.-.
Description
TECHNICAL FIELD
[0001] The present invention relates to quaternary ammonium salts,
electrolytes, electrolytic solutions and electrochemical devices.
More particularly, the invention relates to functional materials
which are usable as electrolytes having a high solubility in
organic solvents, high electrical conductivity and small in
environmental load.
BACKGROUND ART
[0002] In recent years, higher power densities and improved energy
densities have been required of electrochemical devices including
cells and capacitors. Organic electrolytic solutions have found
wider use than aqueous electrolytic solutions from the viewpoint of
voltage resistance. Examples of organic electrolytic solutions are
those prepared by dissolving alkali metal salts or solid ammonium
salts in an organic solvent such as propylene carbonate.
Electrolytic solutions of the former type are used for lithium ion
battery, while those of the latter type are used for electric
double-layer capacitor. Organic electrolytic solutions are inferior
to aqueous solutions in electrical conductivity, and numerous
studies have been made on organic solvents or electrolytes to
obtain improved electrical conductivity.
[0003] The electrical conductivity of nonaqueous electrolytic
solutions comprising such a solid electrolyte dissolved in a
solvent varies with the concentration of the electrolyte. With a
rise in the concentration, the ion concentration of the solution
increases to increase the electrical conductivity, which will reach
a maximum in due course. The electrical conductivity reaching the
maximum starts to decrease presumably because the electrolyte
becomes difficult to dissociate and increases in viscosity at the
same time owing to increased interaction between the solvent and
ions and between the ions as the number of ions increases in the
electrolytic solution. When further increasing in concentration,
the electrolyte becomes no longer dissociable, and the
concentration of the electrolyte is saturated. Thus, an attempt to
increase the concentration of the electrolyte encounters the
problem that the electrolyte becomes less soluble. Another problem
is also experienced in that when electrolytic solutions having an
electrolyte dissolved therein at a high concentration is used in an
environment of low temperature, a salt will separate out to impair
the electrical conductivity of the solution.
[0004] Found in recent years are salts having a melting point
around room temperature or salts having a melting point not higher
than room temperature (salts melting at room temperature). It is
known that even if solid at room temperature, such salts dissolve
in organic solvents at a higher concentration than usual
electrolytes. Furthermore, the salts melting at room temperature
are miscible with a specific organic solvent in a desired ratio.
Accordingly, these salts afford electrolytic solutions having a
high concentration not available by dissolving conventional solid
electrolytes in organic solvents, while although having a high
concentration, the solution is less likely to encounter the problem
that the salt will separate out in a low-temperature environment.
The salt melting at room temperature is itself liquid and is
therefore usable singly as an electrolyte.
[0005] It is disclosed that aliphatic ammonium salts having an
alkoxyalkyl group introduced thereinto are highly soluble in a
nonaqueous organic solvent and are less likely to separate out at
low temperatures (patent literature 1). However, satisfactory
improvements still remain to be made in the electric conductivity
of ionic liquids per se, or in the electric conductivity of
electrolytic solutions as diluted with an organic solvent.
[0006] Many of anions of these electrolytic solutions contain
fluorine, chlorine or like halogen. Many halogen-containing anions
have high electric conductivity and high voltage resistance but
place a heavy burden on the environment. Fluoric anions especially
include many which have the drawback of hydrolyzing in the presence
of water to produce highly toxic hydrogen fluoride. [0007] [patent
literature 1] WO 02/076924
[0008] An object of the present invention is to provide an
electrolyte which is highly soluble in organic solvents, highly
reliable at low temperatures, highly electrically conductive and
less likely to burden the environment, and further to provide
electrochemical device having such advantages.
DISCLOSURE OF THE INVENTION
[0009] The present invention provides the following inventions.
[0010] 1. A quaternary ammonium salt of the formula (1)
##STR00002##
wherein R.sup.1 is straight-chain or branched alkyl having 1 to 4
carbon atoms, R.sup.2 is straight-chain or branched alkyl having 1
to 3 carbon atoms, and X.sup.- is N(CN).sub.2.sup.-, SCN.sup.-,
NO.sub.3.sup.-, NCO.sup.- or NO.sub.2.sup.-.
[0011] 2. A quaternary ammonium salt of the formula (2)
##STR00003##
wherein X.sup.- is same as defined above, and Me is methyl.
[0012] 3. A composition wherein the composition comprises at least
one of quaternary ammonium salts of the formula (1) and the formula
(2), and an organic solvent.
[0013] The present invention provides a quaternary ammonium salt of
the formula (1), and an electrolytic solution containing the
salt
##STR00004##
wherein R.sup.1 is straight-chain or branched alkyl having 1 to 4
carbon atoms, R.sup.2 is straight-chain or branched alkyl having 1
to 3 carbon atoms, and X.sup.- is N(CN).sub.2.sup.-, SCN.sup.-,
NO.sub.3.sup.-, NCO.sup.- or NO.sub.2.sup.-.
[0014] Examples of straight-chain or branched alkyl having 1 to 4
carbon atoms represented by R.sup.1 are methyl, ethyl, n-propyl,
iso-propyl, n-butyl, sec-butyl and tert-butyl. Preferable are
straight-chain or branched alkyl having 1 to 3 carbon atoms. More
preferable are methyl and ethyl.
[0015] Examples of straight-chain or branched alkyl having 1 to 3
carbon atoms represented by R.sup.2 are methyl, ethyl, n-propyl and
iso-propyl. Preferable are methyl and ethyl.
[0016] Examples of quaternary ammonium salts of the present
invention are N-methoxymethyl-N-methylpyrrolidinium dicyanamide,
N-ethyl-N-methoxymethylpyrrolidinium dicyanamide,
N-methoxymethyl-N-n-propylpyrrolidinium dicyanamide,
N-methoxymethyl-N-iso-propylpyrrolidinium dicyanamide,
N-n-butyl-N-methoxymethylpyrrolidinium dicyanamide,
N-iso-butyl-N-methoxymethylpyrrolidinium dicyanamide,
N-tert-butyl-N-methoxymethylpyrrolidinium dicyanamide,
N-methoxymethyl-N-methylpyrrolidinium thiocyanate,
N-ethyl-N-methoxymethylpyrrolidinium thiocyanate,
N-methoxymethyl-N-n-propylpyrrolidinium thiocyanate,
N-methoxymethyl-N-iso-propylpyrrolidinium thiocyanate,
N-n-butyl-N-methoxymethylpyrrolidinium thiocyanate,
N-iso-butyl-N-methoxymethylpyrrolidinium thiocyanate,
N-tert-butyl-N-methoxymethylpyrrolidinium thiocyanate,
N-methoxymethyl-N-methylpyrrolidinium nitrate,
N-ethyl-N-methoxymethylpyrrolidinium nitrate,
N-methoxymethyl-N-n-propylpyrrolidinium nitrate,
N-methoxymethyl-N-iso-propylpyrrolidinium nitrate,
N-n-butyl-N-methoxymethylpyrrolidinium nitrate,
N-iso-butyl-N-methoxymethylpyrrolidinium nitrate,
N-tert-butyl-N-methoxymethylpyrrolidinium nitrate,
N-methoxymethyl-N-methylpyrrolidinium isocyanate,
N-ethyl-N-methoxymethylpyrrolidinium isocyanate,
N-methoxymethyl-N-n-propylpyrrolidinium isocyanate,
N-methoxymethyl-N-iso-propylpyrrolidinium isocyanate,
N-n-butyl-N-methoxymethylpyrrolidinium isocyanate,
N-iso-butyl-N-methoxymethylpyrrolidinium isocyanate,
N-tert-butyl-N-methoxymethylpyrrolidinium isocyanate,
N-methoxymethyl-N-methylpyrrolidinium nitrite,
N-ethyl-N-methoxymethylpyrrolidinium nitrite,
N-methoxymethyl-N-n-propylpyrrolidinium nitrite,
N-methoxymethyl-N-iso-propylpyrrolidinium nitrite,
N-n-butyl-N-methoxymethylpyrrolidinium nitrite,
N-iso-butyl-N-methoxymethylpyrrolidinium nitrite,
N-tert-butyl-N-methoxymethylpyrrolidinium nitrite,
N-ethoxymethyl-N-methylpyrrolidinium dicyanamide,
N-ethoxymethyl-N-ethylpyrrolidinium dicyanamide,
N-ethoxymethyl-N-n-propylpyrrolidinium dicyanamide,
N-ethoxymethyl-N-iso-propylpyrrolidinium dicyanamide,
N-n-butyl-N-ethoxymethylpyrrolidinium dicyanamide,
N-iso-butyl-N-ethoxymethylpyrrolidinium dicyanamide,
N-tert-butyl-N-ethoxymethylpyrrolidinium dicyanamide,
N-ethoxymethyl-N-methylpyrrolidinium thiocyanate,
N-ethoxymethyl-N-ethylpyrrolidinium thiocyanate,
N-ethoxymethyl-N-n-propylpyrrolidinium thiocyanate,
N-ethoxymethyl-N-iso-propylpyrrolidinium thiocyanate,
N-n-butyl-N-ethoxymethylpyrrolidinium thiocyanate,
N-iso-butyl-N-ethoxymethylpyrrolidinium thiocyanate,
N-tert-butyl-N-ethoxymethylpyrrolidinium thiocyanate,
N-ethoxymethyl-N-methylpyrrolidinium nitrate,
N-ethoxymethyl-N-ethylpyrrolidinium nitrate,
N-ethoxymethyl-N-n-propylpyrrolidinium nitrate,
N-ethoxymethyl-N-iso-propylpyrrolidinium nitrate,
N-n-butyl-N-ethoxymethylpyrrolidinium nitrate,
N-iso-butyl-N-ethoxymethylpyrrolidinium nitrate,
N-tert-butyl-N-ethoxymethylpyrrolidinium nitrate,
N-ethoxymethyl-N-methylpyrrolidinium isocyanate,
N-ethoxymethyl-N-ethylpyrrolidinium isocyanate,
N-ethoxymethyl-N-n-propylpyrrolidinium isocyanate,
N-ethoxymethyl-N-iso-propylpyrrolidinium isocyanate,
N-n-butyl-N-ethoxymethylpyrrolidinium isocyanate,
N-iso-butyl-N-ethoxymethylpyrrolidinium isocyanate,
N-tert-butyl-N-ethoxymethylpyrrolidinium isocyanate,
N-ethoxymethyl-N-methylpyrrolidinium nitrite,
N-ethoxymethyl-N-ethylpyrrolidinium nitrite,
N-ethoxymethyl-N-n-propylpyrrolidinium nitrite,
N-ethoxymethyl-N-iso-propylpyrrolidinium nitrite,
N-n-butyl-N-ethoxymethylpyrrolidinium nitrite,
N-iso-butyl-N-ethoxymethylpyrrolidinium nitrite,
N-tert-butyl-N-ethoxymethylpyrrolidinium nitrite,
N-methyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-ethyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-n-propyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-iso-propyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-n-butyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-iso-butyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-tert-butyl-N-n-propoxymethylpyrrolidinium dicyanamide,
N-methyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-ethyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-n-propyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-iso-propyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-n-butyl-N-n-proxymethylpyrrolidinum thiocyanate,
N-iso-butyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-tert-butyl-N-n-propoxymethylpyrrolidinium thiocyanate,
N-methyl-N-n-propoxymethylpyrrolidinium nitrate,
N-ethyl-N-n-propoxymethylpyrrolidinium nitrate,
N-n-propyl-N-n-propoxymethylpyrrolidinium nitrate,
N-iso-propyl-N-n-propoxymethylpyrrolidinium nitrate,
N-n-butyl-N-n-propoxymethylpyrrolidinium nitrate,
N-iso-butyl-N-n-propoxymethylpyrrolidinium nitrate,
N-tert-butyl-N-n-propoxymethylpyrrolidinium nitrate,
N-methyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-ethyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-n-propyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-iso-propyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-n-butyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-iso-butyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-tert-butyl-N-n-propoxymethylpyrrolidinium isocyanate,
N-methyl-N-n-propoxymethylpyrrolidinium nitrite,
N-ethyl-N-n-propoxymethylpyrrolidinium nitrite,
N-n-propyl-N-n-propoxymethylpyrrolidinium nitrite,
N-iso-propyl-N-n-propoxymethylpyrrolidinium nitrite,
N-n-butyl-N-n-propoxymethylpyrrolidinium nitrite,
N-iso-butyl-N-n-propoxymethylpyrrolidinium nitrite,
N-tert-butyl-N-n-propoxymethylpyrrolidinium nitrite,
N-methyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-ethyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-n-propyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-iso-propyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-n-butyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-iso-butyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-tert-butyl-N-iso-propoxymethylpyrrolidinium dicyanamide,
N-methyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-ethyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-n-propyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-iso-propyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-n-butyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-iso-butyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-tert-butyl-N-iso-propoxymethylpyrrolidinium thiocyanate,
N-methyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-ethyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-n-propyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-iso-propyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-n-butyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-iso-butyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-tert-butyl-N-iso-propoxymethylpyrrolidinium nitrate,
N-methyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-ethyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-n-propyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-iso-propyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-n-butyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-iso-butyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-tert-butyl-N-iso-propoxymethylpyrrolidinium isocyanate,
N-methyl-N-iso-propoxymethylpyrrolidinium nitrite,
N-ethyl-N-iso-propoxymethylpyrrolidinium nitrite,
N-n-propyl-N-iso-propoxymethylpyrrolidinium nitrite,
N-iso-propyl-N-iso-propoxymethylpyrrolidinium nitrite,
N-n-butyl-N-iso-propoxymethylpyrrolidinium nitrite,
N-iso-butyl-N-iso-propoxymethylpyrrolidinium nitrite and
N-tert-butyl-N-iso-propoxymethylpyrrolidinium nitrite.
[0017] Preferable are N-methoxymethyl-N-methylpyrrolidinium
dicyanamide, N-ethyl-N-methoxymethylpyrrolidinium dicyanamide,
N-ethoxymethyl-N-methylpyrrolidinium dicyanamide and
N-ethoxymethyl-N-ethylpyrrolidinium dicyanamide.
[0018] Preferable are N-methoxymethyl-N-methylpyrrolidinium
thiocyanate, N-ethyl-N-methoxymethylpyrrolidinium thiocyanate,
N-ethoxymethyl-N-methylpyrrolidinium thiocyanate and
N-ethoxymethyl-N-ethylpyrrolidinium thiocyanate.
[0019] Preferable are N-methoxymethyl-N-methylpyrrolidinium
nitrate, N-ethyl-N-methoxymethylpyrrolidinium nitrate,
N-ethoxymethyl-N-methylpyrrolidinium nitrate and
N-ethoxymethyl-N-ethylpyrrolidinium nitrate.
[0020] Preferable are N-methoxymethyl-N-methylpyrrolidinium
isocyanate, N-ethyl-N-methoxymethylpyrrolidinium isocyanate,
N-ethoxymethyl-N-methylpyrrolidinium isocyanate and
N-ethoxymethyl-N-ethylpyrrolidinium isocyanate.
[0021] Preferable are N-methoxymethyl-N-methylpyrrolidinium
nitrite, N-ethyl-N-methoxymethylpyrrolidinium nitrite,
N-ethoxymethyl-N-methylpyrrolidinium nitrite and
N-ethoxymethyl-N-ethylpyrrolidinium nitrite.
[0022] More preferable are N-methoxymethyl-N-methylpyrrolidinium
dicyanamide and N-ethoxymethyl-N-methylpyrrolidinium
dicyanamide.
[0023] More preferable are N-methoxymethyl-N-methylpyrrolidinium
thiocyanate and N-ethoxymethyl-N-methylpyrrolidinium
thiocyanate.
[0024] More preferable are N-methoxymethyl-N-methylpyrrolidinium
nitrate and N-ethoxymethyl-N-methylpyrrolidinium nitrate.
[0025] More preferable are N-methoxymethyl-N-methylpyrrolidinium
isocyanate and N-ethoxymethyl-N-methylpyrrolidinium isocyanate,
[0026] More preferable are N-methoxymethyl-N-methylpyrrolidinium
nitrite and N-ethoxymethyl-N-methylpyrrolidinium nitrite,
[0027] The quaternary ammonium salt of the present invention can be
prepared by various processes. Typical of these processes are
represented by Equation-1 and Equation-2 given below.
##STR00005##
[0028] An alkylpyrrolidine of the formula (5) wherein R.sup.1 is
the same as above is reacted with a compound of the formula (6)
wherein R.sup.2 is the same as above, and Y is Cl, Br, I or the
like to prepare a quaternary ammonium salt of the formula (1a),
which is then subjected to salt-exchange reaction with a compound
of the formula (7) to prepare a quaternary ammonium salt of the
formula (1) Represented by M in the formula (7) is one of atoms
including hydrogen, alkali metal atoms such as Na, K and Li,
alkaline earth metal atoms such as Ca, Mg and Ba, and metal atoms
such as Ag.
[0029] The tertiary amine of the formula (5) serving as the
starting material and the compound of the formula (6) are both
known substances. Examples of tertiary amine of the formula (5) are
methylpyrrolidine, ethylpyrrolidine, n-propylpyrrolidine,
isopropylpyrrolidine, n-butylpyrrolidine, isobutylpyrrolidine,
tert-butylpyrrolidine, etc.
[0030] Examples of compounds of the formula (6) are chloromethyl
methyl ether, bromomethyl methyl ether, iodomethyl methyl ether,
chloromethyl ethyl ether, bromomethyl ethyl ether, iodomethyl ethyl
ether, chloromethyl n-propyl ether, bromomethyl n-propyl ether,
iodomethyl n-propyl ether, chloromethyl iso-propyl ether,
bromomethyl iso-propyl ether, iodomethyl iso-propyl ether, etc.
[0031] The tertiary amine of the formula (5) and the compound of
the formula (6) are reacted in a suitable solvent.
[0032] The solvent to be used can be a wide variety of known
solvents insofar as they are capable of solving the tertiary amine
of the formula (5) and the compound of the formula (6) and will not
adversely affect the reaction. Examples of such solvents are
benzene, toluene, xylene and like aromatic hydrocarbons,
dichloromethane, chloroform, carbon tetrachloride and like
hydrocarbon halides, methanol, ethanol, isopropanol, n-butanol,
tert-butanol and like lower alcohols, acetone, methyl ethyl ketone
and like ketones, diethyl ether, diisopropyl ether and like ethers,
methyl acetate, ethyl acetate, butyl acetate and like esters,
n-hexane, n-heptane and like aliphatic hydrocarbons, cyclohexane
and like aliphatic hydrocarbons, etc. Preferable among these
solvents are toluene and like aromatic hydrocarbons, chloroform and
like hydrocarbon halides, acetone and like ketones and methyl
acetate and like esters. These solvents can be used singly, or at
least two of them are usable in admixture. Preferable to use are
solvents which are free from water (up to 1000 ppm in water
content).
[0033] The tertiary amine of the formula (5) and the compound of
the formula (6) are used in the ratio usually of 0.5 to 5 moles,
preferably 0.9 to 1.2 moles, of the latter per mole of the
former.
[0034] The reaction is carried out usually at -30 to 100.degree.
C., more particularly at -10 to 40.degree. C. The reaction is
completed generally in several hours to about 24 hours.
[0035] The reaction of the quaternary ammonium salt of the formula
(1a) obtained above with the compound of the formula (7) is carried
out by a usual salt exchange reaction.
[0036] The compound of the formula (7) used as a starting material
is a known compound. Examples of these are HN(CN).sub.2,
LiN(CN).sub.2, NaN(CN).sub.2, KN(CN).sub.2, AgN(CN).sub.2, HSCN,
LiSCN, NaSCN, KSCN, AgSCN, HNO.sub.3, LiNO.sub.3, NaNO.sub.3,
KNO.sub.3, AgNO.sub.3, HNCO, LiNCO, NaNCO, KNCO, AgNCO, HNO.sub.2,
LiNO.sub.2, NaNO.sub.2, KNO.sub.2 and AgNO.sub.2.
[0037] This salt exchange reaction is carried out in a suitable
solvent. The solvent to be used can be a wide variety of known
solvents insofar as they are capable of dissolving the quaternary
ammonium salt of the formula (1a) and the compound of the formula
(7) and will not adversely affect the reaction. Examples of such
solvents are water, dichloromethane, chloroform, carbon
tetrachloride and like hydrocarbon halides, methanol, ethanol,
isopropanol, n-butanol, tert-butanol and like lower alcohols,
acetone, methyl ethyl ketone and like ketones, ethyl acetate, butyl
acetate and like esters, dimethyl sulfoxide, dimethylformamide and
like aprotic polar solvents. Preferable among these are methanol
and like lower alcohols, chloroform and like hydrocarbon halides
and water. These solvents are usable singly, or at least two of
them are usable in admixture.
[0038] The quaternary ammonium salt of the formula (la) and the
compound of the formula (7) are used in the ratio usually of 0.3 to
5 moles, preferably 0.9 to 1.2 moles, of the latter per mole of the
former.
[0039] The reaction proceeds usually rapidly, so that a solution of
the two reactants as dissolved in a solvent is reacted at 5 to
150.degree. C. for about 10 minutes to about 24 hours.
[0040] The desired products obtained by the foregoing respective
reactions can each be readily isolated from the reaction mixture
and purified by usual isolating and purifying means such as
centrifuging, concentration, washing, organic solvent extraction,
chromatography and recrystallization.
[0041] The salt exchange reaction can be carried out with use of an
ion-exchange resin. Examples of the ion-exchange resin are
anion-exchange resin. The salt exchange reaction is performed by
exchanging anions in the resin into desired anions and then passing
into the resin a solution dissolved therein the quaternary ammonium
salt of the formula (1a). The solvent to be used can be a wide
variety of known solvents insofar as they are capable of dissolving
the salt of the formula (1a) and will not adversely affect the
reaction. Examples of such solvents are water and alcohols.
[0042] In the case where the product is to be placed into use in
which the presence of halogen in the product is objectionable, the
amount of halogen present can be diminished by subjecting the
halogen salt to neutralization or salt exchange, and further
converting the product into a salt in conformity with the
contemplated use. Examples of useful neutralizing agents are alkali
metal salts, alkaline earth metal salts, organic alkali metal
salts, silver salts, etc. More specific examples of such agents are
sodium carbonate, potassium carbonate, lithium carbonate, calcium
carbonate, sodium hydroxide, potassium hydroxide, lithium
hydroxide, calcium hydroxide, sodium perchlorate, potassium
perchlorate, lithium perchlorate, sodium acetate, potassium
acetate, silver sulfate, silver nitrate, silver perchlorate,
etc.
[0043] The reaction can be carried out in the same mode as the
procedure for preparing the quaternary ammonium salt of the formula
(1). The procedure for preparing the quaternary ammonium salt of
the formula (1) is usable also as the subsequent procedure for
converting the dehalogenated salt into a salt in conformity with
the contemplated use.
[0044] Stated specifically, the quaternary ammonium salt of the
formula (1) wherein X is N(CN).sub.2 is prepared from a quaternary
ammonium salt of the formula (1a) by the reaction procedure to be
described below.
[0045] The quaternary ammonium salt of the formula (1a) is
dissolved in water, and a specified amount of silver dicyanamide is
added to the solution to conduct a reaction at 5 to 150.degree. C.
for about 10 hours. The silver halide or the like is filtered off,
and the filtrate is concentrated in a vacuum and dried, whereby the
desired compound can be isolated. It is preferable to pass the
filtrate through an alumina column to remove impurities such as
very small amount of silver dicyanamide.
##STR00006##
[0046] An alkoxypyrrolidine of the formula (8) wherein R.sup.2 is
the same as above is reacted with a compound of the formula (9)
wherein R.sup.1 and Y are the same as above to prepare a quaternary
ammonium salt of the formula (1a), which is then reacted with a
compound of the formula (7) wherein M and X are the same as above
to thereby prepare a quaternary ammonium salt of the formula (1) by
salt exchange reaction. Represented by M in the formula (7) is one
of atoms including hydrogen, alkali metal atoms such as Na, K and
Li, alkaline earth metal atoms such as Ca, Mg and Ba, and metal
atoms such as Ag.
[0047] The alkoxypyrrolidine of the formula (8) serving as the
starting material and the compound of the formula (9) are both
known substances.
[0048] The alkoxypyrrolidine of the formula (8) is prepared by
known processes. Such processes are disclosed, for example, in C.
M. McLeod und G. M. Robinson, J. Chem. Soc. 119, 1470(1921), G. M.
Robinson und R. Robinson, J. Chem. Soc. 123, 532(1923), Stewert, T.
D.; Bradly, W. E., J. Am. Chem. Soc. 1932, 54, 4172-4183.
[0049] The alkoxypyrrolidine of the formula (8) is prepared
generally by using pyrrolidine, formaldehyde or p-formaldehyde,
alcohol, and alkali carbonate. Used per mole of pyrrolidine are 0.5
to 3.0. moles, preferably 0.6 to 1.5 moles of 10 to 38 wt % aqueous
solution of formaldehyde or p-formaldehyde, 0.5 to 3.0 moles,
preferably 2.0 to 3.0 moles of an alcohol, and 0.2 to 3.0 moles,
preferably 0.4 to 1.0 mole of an alkali carbonate. The reaction is
carried out at a temperature of -5 to 25.degree. C. when aqueous
solution of formaldehyde is used, and 60 to 100.degree. C. when
aqueous solution of p-formaldehyde is used, and is completed in
several hours to about 24 hours. The alkoxypyrrolidine of the
formula (8) can be readily isolated from the reaction mixture and
purified by usual isolating means such as extraction and
rectification.
[0050] Examples of the compound of the formula (9) are methyl
chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl
iodide, ethyl bromide, n-propyl chloride, n-propyl bromide,
n-propyl iodide, iso-propyl chloride, iso-propyl bromide,
iso-propyl iodide, n-butyl chloride, n-butyl bromide, n-butyl
iodide, iso-butyl chloride, iso-butyl bromide, iso-butyl iodide,
tert-butyl chloride, tert-butyl bromide and tert-butyl iodide.
[0051] The alkoxypyrrolidine of the formula (8) is reacted with the
compound of the formula (9) in a suitable solvent.
[0052] The solvent to be used can be a wide variety of those
already known insofar as they are capable of dissolving the
alkoxypyrrolidine of the formula (8) and the compound of the
formula (9) and will not adversely affect the reaction. Examples of
such solvents are benzene, toluene, xylene and like aromatic
hydrocarbons, dichloromethane, chloroform, carbon tetrachloride and
like hydrocarbon halides, methanol, ethanol, isopropanol,
n-butanol, tert-butanol and like lower alcohols, acetone, methyl
ethyl ketone and like ketones, diethyl ether, diisopropyl ether and
like ethers, methyl acetate, ethyl acetate, butyl acetate and like
esters, n-hexane, n-heptane and like aliphatic hydrocarbons,
cyclohexane and like aliphatic hydrocarbons, etc. Preferable among
these solvents are acetone and like ketone, toluene and like
aromatic hydrocarbons, and chloroform and like hydrocarbon halides.
These solvents can be used singly, or at least two of them are
usable in admixture. Especially preferable to use are solvents
which are free from water (up to 1000 ppm in water content).
[0053] The alkoxypyrrolidine of the formula (8) and the compound of
the formula (9) are used in the ratio usually of 0.5 to 5 moles,
preferably 0.9 to 1.2 moles, of the latter per mole of the
former.
[0054] The reaction is carried out usually at 0 to 150.degree. C.
The reaction is completed generally in about 24 hours to about 72
hours. When an alkyl halide having a low boiling point is used for
producing the quaternary salt, it is desirable to use an
autoclave.
[0055] The reaction of the quaternary ammonium salt of the formula
(1a) obtained above with the compound of the formula (7) is carried
out by a usual salt exchange reaction.
[0056] The compound of the formula (7) serving as the starting
material is a known compound. Examples of thereof are HN(CN).sub.2,
LiN(CN).sub.2, NaN(CN).sub.2, KN(CN).sub.2, AgN(CN).sub.2, HSCN,
LiSCN, NaSCN, KSCN, AgSCN, HNO.sub.3, LiNO.sub.3, NaNO.sub.3,
KNO.sub.3, AgNO.sub.3, HNCO, LiNCO, NaNCO, KNCO, AgNCO, HNO.sub.2,
LiNO.sub.2, NaNO.sub.2, KNO.sub.2 and AgNO.sub.2.
[0057] This salt exchange reaction is carried out in a suitable
solvent. The solvent to be used can be a wide variety of known
solvents insofar as they are capable of dissolving the quaternary
ammonium salt of the formula (1a) and the compound of the formula
(7) and will not adversely affect the reaction. Examples of such
solvents are water, dichloromethane, chloroform, carbon
tetrachloride and like hydrocarbon halides, methanol, ethanol,
isopropanol, n-butanol, tert-butanol and like lower alcohols,
acetone, methyl ethyl ketone and like ketones, ethyl acetate, butyl
acetate and like esters, dimethyl sulfoxide, dimethylformamide and
like aprotic polar solvents. Preferable among these are methanol
and like lower alcohols, chloroform and like hydrocarbon halides
and water. These solvents are usable singly, or at least two of
them are usable in admixture.
[0058] The quaternary ammonium salt of the formula (1a) and the
compound of the formula (7) are used in the ratio usually of 0.3 to
5 moles, preferably 0.9 to 1.2 moles, of the latter per mole of the
former. The reaction proceeds usually rapidly, so that a solution
of the two reactants in a solvent is reacted at about 5 to about
150.degree. C. for about 10 minutes to about 24 hours.
[0059] The desired products obtained by the foregoing respective
reactions can each be readily isolated from the reaction mixture
and purified by usual isolating and purifying means such as
centrifuging, concentration, washing, organic solvent extraction,
chromatography and recrystallization.
[0060] The salt exchange reaction can also be carried out with use
of an ion-exchange resin. Examples of the ion-exchange resin are
anion-exchange resin. The salt exchange reaction is performed by
exchanging anions in the resin into desired anions and then passing
into the resin a solution dissolved therein the quaternary ammonium
salt of the formula (1a). The solvent to be used can be a wide
variety of known solvents insofar as they are capable of dissolving
the salt of the formula (1a) and will not adversely affect the
reaction. Examples of such solvents are water and alcohols.
[0061] In the case where the product is to be placed into use in
which the presence of halogen in the product is objectionable, the
amount of halogen present can be diminished by subjecting the
halogen salt to neutralization or salt exchange, and further
converting the product into a salt in conformity with the
contemplated use. Examples of useful neutralizing agents are alkali
metal salts, alkaline earth metal salts, organic alkali metal
salts, silver salts, etc. More specific examples of such agents are
sodium carbonate, potassium carbonate, lithium carbonate, calcium
carbonate, sodium hydroxide, potassium hydroxide, lithium
hydroxide, calcium hydroxide, sodium perchlorate, potassium
perchlorate, lithium perchlorate, sodium acetate, potassium
acetate, silver sulfate, silver nitrate, silver perchlorate,
etc.
[0062] The reaction can be carried out in the same mode as the
procedure for preparing the quaternary ammonium salt of the formula
(1). The procedure for preparing the quaternary ammonium salt of
the formula (1) is usable also as the subsequent procedure for
converting the dehalogenated salt into a salt in conformity with
the contemplated use.
[0063] Stated specifically, the quaternary ammonium salt of the
formula (1) wherein X is N(CN).sub.2 is prepared from a quaternary
ammonium salt of the formula (1a) by the reaction procedure to be
described below.
[0064] The quaternary ammonium salt of the formula (1a) is
dissolved in water, and a specified amount of silver dicyanamide is
added to the solution to conduct a reaction at 5 to 150.degree. C.
for about 10 hours. The silver halide or the like is filtered off,
and the filtrate is concentrated in a vacuum and dried, whereby the
desired compound can be isolated. It is preferable to pass the
filtrate through an alumina column to remove impurities such as
very small amount of silver dicyanamide.
[0065] The quaternary ammonium salt of the formula (1) contains
water in an amount of preferably up to 100 ppm, more preferably up
to 50 ppm, further more preferably up to 30 ppm, especially most
preferably up to 10 ppm. When the quaternary ammonium salt of the
formula (1) of the invention itself is a liquid at room
temperature, the salt is usable as it is as an electrolytic
solution. These salts are usable singly, or at least two of them
are usable in admixture.
[0066] The quaternary ammonium salt of the formula (1) of the
invention is usable as an electrolytic solution as mixed with a
suitable organic solvent. Also these salts are usable singly, or at
least two of them are usable in admixture.
##STR00007##
[0067] Examples of organic solvents are cyclic carbonic acid
esters, chain carbonic acid esters, phosphoric acid esters, cyclic
ethers, chain ethers, lactone compounds, chain esters, nitrile
compounds, amide compounds, sulfone compounds, etc. These solvents
may be used singly, or at least two of them are usable in
admixture.
[0068] Although not limitative, the solvents given below are more
specific examples of useful solvents.
[0069] Examples of cyclic carbonic acid esters are ethylene
carbonate, propylene carbonate, butylene carbonate, etc. Preferable
is propylene carbonate.
[0070] Examples of chain carbonic acid esters are dimethyl
carbonate, ethylmethyl carbonate, methyl-n-propyl carbonate,
methyl-isopropyl carbonate, n-butylmethyl carbonate, diethyl
carbonate, ethyl-n-propyl carbonate, ethyl-iso-propyl carbonate,
n-butylethyl carbonate, di-n-propyl carbonate, di-iso-propyl
carbonate and di-n-butyl carbonate. Preferable are dimethyl
carbonate and ethylmethyl carbonate.
[0071] Examples of phosphoric acid esters are trimethyl phosphate,
triethyl phosphate, ethyldimethyl phosphate, diethylmethyl
phosphate, etc.
[0072] Examples of cyclic ethers are tetrahydrofuran,
2-methyltetrahydrofuran, etc.
[0073] Examples of chain ethers are dimethoxyethane, etc.
[0074] Examples of lactone compounds are gamma-butyrolactone and
the like.
[0075] Examples of chain esters are methyl propionate, methyl
acetate, ethyl acetate, methyl formate, etc.
[0076] Examples of nitrile compounds are acetonitrile and the
like.
[0077] Examples of amide compounds are dimethylformamide and the
like.
[0078] Examples of sulfone compounds are sulfolane, methyl
sulfolane, etc.
[0079] Preferable are cyclic carbonic acid esters, chain carbonic
acid esters, nitrile compounds and sulfone compounds.
[0080] These solvents may be used singly, or at least two of them
are usable in admixture.
[0081] Examples of mixtures of solvents are a mixture of cyclic
carbonic acid ester and chain carbonic acid ester, a mixture of
chain carbonic acid ester and chain carbonic acid ester and a
mixture of sulfolane compound and sulfolane compound.
[0082] Examples of mixtures of cyclic carbonic acid ester and chain
carbonic acid ester are ethylene carbonate and dimethyl carbonate;
ethylene carbonate and ethylmethyl carbonate; ethylene carbonate
and diethyl carbonate; propylene carbonate and dimethyl carbonate;
propylene carbonate and ethylmethyl carbonate; propylene carbonate
and diethyl carbonate; etc.
[0083] Examples of mixtures of chain carbonic acid ester and chain
carbonic acid ester are dimethyl carbonate and ethylmethyl
carbonate.
[0084] Examples of mixtures of sulfolane compound and sulfolane
compound are sulfolane and methyl sulfolane.
[0085] Preferable examples of mixtures are ethylene carbonate and
ethylmethyl carbonate; propylene carbonate and ethylmethyl
carbonate; dimethyl carbonate and ethylmethyl carbonate; etc.
[0086] When the electrolyte of the quaternary ammonium salt of the
formula (1) of the invention is used as dissolved in an organic
solvent, the concentration of the electrolyte is at least 0.1 M,
preferably at least 0.5 M and more preferably at least 1 M.
[0087] The quaternary ammonium salt of the formula (1) of the
invention or a solution of such a salt as dissolved in an organic
solvent is usable as an electrolytic solution for electrochemical
devices.
[0088] Examples of electrochemical devices are electric
double-layer capacitors and secondary cells.
[0089] Electrolyte or electrolytic solution of the invention is
usable as those used in known electrolytes or electrolytic
solutions for electric double-layer capacitors or secondary
batteries.
[0090] When the electrolyte of the quaternary ammonium salt of the
formula (1) of the invention is used as dissolved in an organic
solvent for electrolytic solutions of electrochemical devices, the
concentration of the electrolyte is at least 0.1 M, preferably at
least 0.5 M and more preferably at least 1 M. If the concentration
is lower than 0.1 M, the solution is low in electrical
conductivity, providing electrochemical devices of impaired
performance. The upper limit concentration is the concentration
permitting the quaternary ammonium salt to separate from the
organic solvent when the salt is liquid at room temperature. If the
salt is free of separation, the upper limit concentration is 100%.
When the quaternary ammonium salt is solid at room temperature, the
concentration at which the organic solvent becomes saturated with
the salt is the upper limit concentration.
[0091] An electrolytic solution for electrochemical devices can be
prepared using the quaternary ammonium salt of the formula (1) of
the invention. The electrolytic solution obtained by the invention
is usable for electrochemical devices wherein electric energy can
be stored by a physical activity or chemical activity and can be
used suitably for example in electric double-layer capacitor and
lithium batteries.
[0092] A description will be given of a method of preparing an
electrolytic solution for use in electric double-layer capacitor
using the quaternary ammonium salt of the formula (1) of the
invention. When the quaternary ammonium salt of the formula (1) of
the invention itself is a liquid, the salt is usable as it is as an
electrolytic solution, while the salt may be used as mixed with a
suitable organic solvent. In preparing electrolytic solution for
use in electric double-layer capacitor, since water adversely
affects the performance of electric double-layer capacitors, it is
desirable to conduct the work free from the atmospheric air, for
example, within a glove box having an inert atmosphere of argon or
nitrogen. The water content of the work environment can be
controlled using a dewpoint meter and is preferably up to minus
60.degree. C. When the work environment is in excess of minus
60.degree. C. and if the work is carried out over a prolonged
period of time, the electrolyte or electrolytic solution will
absorb water from the atmosphere and therefore rises in water
content. The water content of the electrolyte or electrolytic
solution can be measured by a Karl Fischer moisture meter.
[0093] In the case where a solution of the quaternary ammonium salt
of the formula (1) of the invention in an organic solvent is to be
used as the electrolytic solution of electrochemical devices, the
concentration of the electrolyte is preferably at least 0.1 M, more
preferably at least 0.5 M, especially preferably at least 1 M. The
upper limit concentration is not defined insofar as no
precipitation or separation of the electrolyte occurs.
[0094] Examples of organic solvents to be used are various as
previously mentioned, whereas since the properties such as
dielectric constant, viscosity and melting point differ depending
on the combination of the quaternary ammonium salt of the invention
and the kind of solvent to be mixed therewith, it is desirable to
determine the composition of the mixture in accordance with the
combination of the quaternary ammonium salt of the formula (1) of
the invention and the solvent to be mixed therewith for use.
[0095] For example, in the case of an electrolytic solution
comprising N-methoxymethyl-N-methylpyrrolidinium dicyanamide and
propylene carbonate, the solution comprises preferably 30 to 80 wt.
%, more preferably 40 to 80 wt. % of the dicyanamide. In the case
of an electrolytic solution comprising
N-methoxymethyl-N-methylpyrrolidinium dicyanamide and acetonitrile,
the solution comprises preferably 20 to 80 wt. %, more preferably
40 to 60 wt. % of the dicyanamide.
[0096] The quaternary ammonium salt of the formula (1) of the
invention is usable as an electrolytic solution also for secondary
batteries, especially for lithium secondary batteries. Since water
adversely affects the characteristics of lithium batteries as when
the electrolytic solution of electric double-layer capacitor is
prepared, the solution is prepared preferably within a glove box
having its dewpoint controlled.
[0097] In the case where the quaternary ammonium salt of the
formula (1) of the invention itself is a liquid, the salt is usable
as an electrolytic solution when having a lithium salt dissolved
therein. Alternatively, the quaternary ammonium salt of the formula
(1) of the invention is admixed with a suitable organic solvent,
and a lithium salt is dissolved in the mixture for use as an
electrolytic solution. Examples of the lithium salts are lithium
hexafluorophosphate lithium borofluoride, lithium perchlorate,
lithium trifluoromethanesulfonate, lithium sulfonylimide and
lithium sulfonylmethide. The lithium salt to be used can be a wide
variety of salts and is not limited particularly insofar as the
solution is free of separation of the salt.
[0098] The concentration of the lithium salt is usually 0.1 to 2.0
moles, preferably 0.15 to 1.5 moles, more preferably 0.2 to 1.2,
especially preferably 0.3 to 1.0 moles. If the concentration is
less than 0.1 mole and when the charge-discharge rate is great,
depletion of lithium ion occurs in the vicinity of the electrode to
result in impaired charge-discharge characteristics. If the lithium
ion concentration is over 2.0 moles, the electrolytic solution has
a high viscosity to entail lower electrical conductivity.
[0099] The quaternary ammonium salt is usable as an electrolytic
solution as mixed with a suitable organic solvent. Also these salts
are usable singly, or at least two of them are usable in
admixture.
[0100] Examples of organic solvents are same as those stated above
and are cyclic carbonic acid esters, chain carbonic acid esters,
phosphoric acid esters, cyclic ethers, chain ethers, lactone
compounds, chain esters, nitrile compounds, amide compounds,
sulfone compounds, etc. These solvents may be used singly, or at
least two of them are usable in admixture.
[0101] It is desired that the electrolytic solution to be used in
the present invention contain at least one of specific organic
additives. Examples of specific organic additives are ethylene
carbonate, vinylene carbonate, butylene carbonate, ethylene
trithiocarbonate, vinylene trithiocarbonate and ethylene sulfite.
Preferable are ethylene carbonate and vinylene carbonate. These
additives may be used singly, or at lest two of them are usable in
admixture. The organic additive incorporated into the solution
forms on the surface of the negative electrode of the lithium cell
a film known as SEI (solid electrolyte interface) for lithium ions
to permeate therethrough selectively, inhibiting the decomposition
of ammonium cations which form the quaternary ammonium salt or
insertion of ammonium cations into the negative electrode material
and consequently giving stabilized charge-discharge
characteristics. Some kinds of such organic additives are
substances also having the function of a diluting organic
solvent.
[0102] The organic additive is used preferably in a proportion
preferably of 1 to 40 wt. %, more preferably 1 to 30 wt. %, further
more preferably 1 to 20 wt. %, most preferably 1 to 10 weight %,
based on the weight of the entire electrolytic solution. If the
proportion is less than 1 wt. %, a satisfactory film will not be
formed over the surface of the negative electrode, permitting the
decomposition of ammonium cations which form the quaternary
ammonium salt or insertion of ammonium cations into the negative
electrode material.
[0103] Electric double layer capacitor can be favorably fabricated
using the electrolytic solution of the invention thus obtained.
FIG. 1 shows an example of electric double layer capacitor.
Electric double layer capacitors are not limited to those of coin
shape as shown in FIG. 1. Such a capacitor may be in the form of an
assembly of superposed electrodes as placed in a can, a roll of
electrodes as wound up and placed in a can, or a so-called laminate
as packaged in an aluminum laminate. A description will be given of
the structure of the coin-shaped electric double layer capacitor as
an example.
[0104] FIG. 1 is a diagram showing the coin-shaped electric double
layer capacitor in section. Electrodes 1, 2 are arranged as opposed
to each other with a separator interposed therebetween, and are
housed in container members 4, 5. The electrode comprises a
polarizable electrode portion made of a carbon material such as
activated carbon, and a current collector portion. The container
members 4, 5 need only to be free of corrosion with the
electrolytic solution and are made, for example, from stainless
steel, aluminum or the like. The container members 4, 5 are
electrically insulated with an insulation gasket 6, which also
hermetically seals off the interior of a metal container to prevent
water and air from ingressing into the interior from outside the
container. The current collector of the electrode 1 and the
container member 4, as well as the current collector of the
electrode 2 and a metal spacer 7, are held in contact with each
other under suitable pressure by the presence of a metal spring 8,
and are thereby electrically connected. To ensure enhanced electric
conductivity, the current collector may be adhered with a carbon
paste or like conductive paste.
[0105] The polarizable electrode is made preferably from a material
having a great specific surface area and high electric
conductivity. The material needs to be electrochemically stable to
the electrolytic solution within the range of voltages to be
applied for use. Examples of such materials are carbon materials,
metal oxide materials, conductive high-molecular-weight materials,
etc. In view of the cost, the material for the polarizable
electrode is preferably carbon material.
[0106] Activated carbon materials are desirable as carbon
materials. Examples of such materials are sawdust activated carbon,
coconut shell activated carbon, pitch or coke activated carbon,
phenolic resin activated carbon, polyacrylonitrile activated
carbon, celluosic activated carbon, etc.
[0107] Examples of metal oxide materials usable are ruthenium
oxide, manganese oxide, cobalt oxide, etc.
[0108] Examples of conductive high-molecular-weight materials to be
used are polyaniline, polypyrrole film, polythiophene film,
poly(3,4-ethylenedioxythiophene) film, etc.
[0109] The electrode can be obtained by molding the polarizable
electrode material and a binder by press work, or by admixing the
polarizable electrode material with a binder and an organic solvent
such as pyrrolidine to prepare a paste, coating aluminum foil or
like current collector with the paste and drying the coated current
collector.
[0110] Preferably, the separator has high electron insulating
properties, is highly wettable with the electrolytic solution and
highly permeable to ions, and needs to be electrochemically stable
within the range of voltages to be applied. Although the material
for the separator is not limited particularly, it is suitable to
use paper made from rayon, Manila hemp or the like, porous
polyolefin film, nonwoven polyethylene fabric, nonwoven
polypropylene fabric, etc.
[0111] The electrolytic solution according to the invention and
thus prepared is suitable for use in fabricating lithium secondary
batteries. The lithium secondary battery of the invention is, for
example, in the form of a coin, hollow cylinder, square or
rectangle or laminate. FIG. 2 shows a coin-shaped battery as an
example of lithium secondary cell.
[0112] The lithium secondary battery will be described below based
on FIG. 2.
[0113] Into internal space defined by a positive electrode can 14
and a negative electrode can 15 are placed a positive electrode 11,
separator 13, negative electrode 12 and spacer 17 in this order to
provide a stack of superposed layers as positioned on the positive
electrode can 14. A spring 18 is interposed between the negative
electrode can 15 and the spacer 17 to press the positive electrode
11 and the negative electrode 12 against each other and fixedly
position the electrodes in place. The assembly of positive
electrode 11, separator 13 and negative electrode 12 is impregnated
with the electrolytic solution. With a gasket 16 provided between
the positive and negative cans 14, 15, the two cans 14 and 15 are
joined by crimping, whereby the stack of components is enclosed as
sealed off.
[0114] Examples of positive electrode active substances are
composite oxides of lithium and transition metal or metals, such as
LiCoO.sub.2, LiNiO.sub.2, LiNi.sub.1-xCo.sub.xO.sub.2,
LiNi.sub.1-y-zCo.sub.yMn.sub.zO.sub.2,
LiNi.sub.0.5Mn.sub.0.50O.sub.2, LiMnO.sub.2, LiMn.sub.2O.sub.4 and
LiNi.sub.0.5Mn.sub.1.5O.sub.4, oxides such as TiO.sub.2 and
V.sub.2O.sub.5, sulfides such as TiS.sub.2 and FeS, etc. From the
viewpoint of cell capacity and energy density, composite oxides of
lithium and transition metal or metals are desirable.
[0115] In the above, 1>x>0, 1>y>0, 1>z>0,
y+z<1. Such a positive electrode active substance can be molded
into a positive electrode along with known auxiliary conductive
agent and binder under pressure. Alternatively, the positive
electrode can be made by mixing the positive electrode active
substance with pyrrolidine or like organic solvent along with known
conductive agent and binder to prepare a paste, coating a current
collector of aluminum foil with the paste and drying the
coating.
[0116] Examples of negative electrode active substances are a metal
lithium, alloy of metal lithium and other metal, and a material for
lithium ions to be inserted thereinto and to be released therefrom.
Examples of alloys of metal lithium and other metals are Li--Al,
Li--Sn, Li--Zn, Li--Si, etc. Examples of materials for lithium ions
to be inserted thereinto and to be released therefrom are carbon
materials prepared by firing a resin or pitch, a carbon material
obtained by adding a boron compound to such a carbon material,
natural graphite, etc. These negative electrode materials can be
used singly, or at least two of them are usable in admixture.
[0117] Such a negative electrode material can be molded into a
negative electrode along with known auxiliary conductive agent and
binder under pressure. Alternatively, the negative electrode can be
made by mixing the negative electrode active substance with
pyrrolidone or like organic solvent along with known conductive
agent and binder to prepare a paste, coating a current collector of
copper foil with the paste and drying the coating.
[0118] The separator for use in the invention can be made from a
material which is not limited particularly insofar as the material
readily passes the electrolytic solution therethrough, has
insulating properties and is chemically stable.
[0119] The quaternary ammonium salt of the formula (1) of the
invention and the electrolytic solution containing the salt are
high in electrical conductivity and solubility in organic solvents,
and are suitable for use as an electrolytic solution for
electrochemical devices. Examples of electrochemical devices are
electric double-layer capacitor, secondary batteries, solar cells
of the pigment sensitizer type, electrochromic devices, condenser,
etc., which are nevertheless not limitative. Especially suitable as
electrochemical devices are electric double-layer capacitor and
secondary batteries.
BRIEF DESCRIPTION OF THE DRAWINGS
[0120] FIG. 1 is a sectional view showing an electric double-layer
capacitor of the invention.
[0121] FIG. 2 is a sectional view showing a lithium secondary cell
of the invention.
[0122] 1 electrode, 2 electrode, 3 separator, 4 container member, 5
container member, 6 gasket, 7 spacer, 8 spring, 11 positive
electrode, 12 negative electrode, 13 porous separator, 14 positive
electrode can, 15 negative electrode can, 16 gasket, 17 spacer, 18
spring
BEST MODE OF CARRYING OUT THE INVENTION
[0123] The present invention will be described with reference to
the following Examples, but is not limited to these examples.
Organic solvents used such as propylene carbonate, acetonitrile,
etc. are products of Kishida Chemical Co., Ltd., lithium battery
grade. Water content was measured by a Karl Fischer moisture meter
(Hiranuma Moisture Meter AQ-7, product of Hiranuma Sangyo Co.,
Ltd.).
Preparation Example 1
Preparation of N-methoxymethyl-N-methylpyrrolidinium chloride
[0124] A 50.0 g quantity of N-methylpyrrolidine (reagent, product
of Tokyo Kasei Co., Ltd., purified by rectification, up to 0.1 wt.
% of both of pyrrolidine and water) was dissolved in 292.0 g of
dehydrated acetone (up to 0.1 wt. % of water content), followed by
replacement with nitrogen. Chloromethyl methyl ether (47.3 g,
reagent, product of Tokyo Kasei Co., Ltd., purified by
distillation) was added dropwise to the solution at 5.degree. C.
over a period of 1 hour. The mixture was stirred at 5 to 15.degree.
C. for 4 hours to complete the reaction. The reaction mixture was
filtered, and the resulting solid product was washed with 120 g of
acetone. The washed product was dried in a vacuum to obtain 92.5 g
of the desired product (white solid).
[0125] .sup.1H-NMR (CD.sub.3OD) .delta.ppm:
[0126] 2.22(m 4H), 3.11(s 3H), 3.46(m 2H), 3.60(m 2H), 3.67(s 3H),
4.65(s 2H)
Preparation Example 2
Preparation of N-ethyl-N-methoxymethylpyrrolidinium chloride
[0127] A 34.71 g quantity of N-ethylpyrrolidine (reagent, product
of Tokyo Kasei Co., Ltd., purified by rectification, up to 0.1 wt.
% of both of pyrrolidine and water) was dissolved in 189 g of
dehydrated acetone (up to 0.1 wt. % of water content), followed by
replacement with nitrogen. Chloromethyl ethyl ether (28.18 g) was
added dropwise to the solution at 5.degree. C. over a period of 1
hour. The mixture was stirred at 5.degree. C. for 5 hours to
complete the reaction. The reaction mixture was filtered, and the
resulting solid product was washed with 100 g of acetone. The
washed product was dried in a vacuum to obtain 50.08 g of white
solid.
[0128] .sup.1H-NMR (CD.sub.3OD) .delta.ppm:
[0129] 1.36(m 3H), 2.17(m 4H), 3.41-3.64(m 6H), 3.64(s 3H), 4.59(s
2H)
Preparation Example 3
Preparation of N-ethoxymethyl-N-methylpyrrolidinium chloride
[0130] A 87.0 g quantity of N-methylpyrrolidine (reagent, product
of Tokyo Kasei Co., Ltd., purified by rectification, up to 0.1 wt.
% of both of pyrrolidine and water) was dissolved in 510 g of
dehydrated acetone (up to 0.1 wt. % of water content), followed by
replacement with nitrogen. Chloromethyl ethyl ether (96.6 g) was
added dropwise to the solution at 3.degree. C. over a period of 1
hour. The mixture was stirred at 5 to 15.degree. C. for 4 hours to
complete the reaction. The reaction mixture was concentrated and
dried in a vacuum at reduced pressure. To the resulting product was
added 700 ml of a solvent mixture of 2-butanone/acetone (8/2=v/v)
and recrystallized at -30.degree. C. The precipitate was filtered,
and the resulting solid product was washed with a solvent mixture
of 2-butanone/acetone. The washed product was dried in a vacuum to
obtain 183.4 g of the desired product (white crystal).
[0131] .sup.1H-NMR (CD.sub.3OD) .delta.ppm:
[0132] 1.30(t 3H), 2.23(m 4H), 3.12(s 3H), 3.47(m 2H), 3.60(m 2H),
3.89(q 2H), 4.71(s 2H)
Example 1
Preparation of N-methoxymethyl-N-methylpyrrolidinium
dicyanamide
[0133] In 321.1 g of water was dissolved 68.5 g of
N-methoxymethyl-N-methylpyrrolidinium chloride and thereto was
added 72.2 g of silver dicyanamide. The mixture was reacted at
50.degree. C. for 9 hours, cooled to room temperature and filtered.
The filtrate was concentrated at reduced pressure and dried in
vacuum. To the resulting product was added 500 ml of dehydrated
dichloromethane (reagent, Kanto Kagaku Co., Ltd.) and cooled to
-25.degree. C. The mixture was filtered, concentrated and dried in
vacuum. The residue was purified through alumina column (ICN
Biomedicals. GmbH, ICN Alumina N, Act.1/eluent acetonitrile). The
eluate was concentrated and dried in vacuum to obtain 80.1 g of the
desired product (colorless liquid). The product was checked for
.sup.1H-NMR, electrical conductivity and voltage resistance.
[0134] The electrical conductivity was measured using an electrical
conductivity meter (product of Radiometer Analytical SAS). The
measuring cell used was CDC641T, product of Radiometer Analytical
SAS.
[0135] The voltage resistance was measured using a 3-electrode
electrochemical cell. Used as the working electrode was a glassy
carbon electrode (product of BAS Inc.) 1.0 mm in diameter and
0.0079 cm.sup.-2 in electrode area. The reference electrode used
was a silver wire (product of the Nilaco Corp., 99.99% in purity)
having a diameter of 0.5 mm. The counter electrode used was a
platinum electrode (product of BAS Inc. 11-2233) measuring 0.5 mm
in diameter and 50 mm in length. Linear sweep voltammetry was
carried out to individually determine the potentials giving an
oxidizing current density and reducing current density of 0.5
mAcm.sup.-2. The difference between the potentials was taken as the
voltage resistance. The potential sweep application speed was 50
mVs.sup.-1. HZ-3000, product of Hokuto Denko Co., Ltd. was used for
electrochemical measurement.
[0136] .sup.1H-NMR (CD.sub.3OD) .delta.ppm:
[0137] 2.22(m 4H), 3.10(s 3H), 3.45(m 2H), 3.58(m 2H), 3.67(s 3H),
4.60(s 2H)
[0138] electrical conductivity: 21.60 mS/cm (25.degree. C.)
[0139] voltage resistance: 4.3V
Example 2
Preparation of N-methoxymethyl-N-methylpyrrolidinium
thiocyanate
[0140] In 260 g of ethanol was dissolved 51.0 g of sodium
thiocyanate (reagent, Wako Pure Chemical Ind. Ltd.). In 50.3 g of
ethanol was dissolved 80.2 g of
N-methoxymethyl-N-methylpyrrolidinium chloride. The latter solution
was added dropwise to the former solution at room temperature over
a period of 0.5 hour to perform salt exchange. The mixture was
stirred at room temperature for 36 hours to complete the reaction
and filtered. The resulting solid product was washed with 300 g of
ethanol. The filtrate was dried at reduced pressure and the residue
was purified through alumina column (ICN Biomedicals. GmbH, ICN
Alumina N, Act.1/eluent acetonitrile). The eluate was concentrated
and dried in vacuum to obtain 82.0 g of the desired product
(colorless liquid). The product was checked for .sup.1H-NMR,
electrical conductivity and voltage resistance as in Example 1.
[0141] .sup.1H-NMR(CD3OD) .delta.ppm:
[0142] 2.23(m 4H), 3.13(s 3H), 3.49(m 2H), 3.62(m 2H), 3.68(s 3H),
4.65(s 2H)
[0143] electrical conductivity: 14.06 mS/cm(25.degree. C.)
[0144] voltage resistance:3.4V
Example 3
Preparation of N-methoxymethyl-N-methylpyrrolidinium nitrate
[0145] In 150.4 g of water was dissolved 49.8 g of
N-methoxymethyl-N-methylpyrrolidinium chloride and thereto was
added 56.1 g of silver nitrate. The mixture was reacted at room
temperature for 2 hours, cooled to 5.degree. C. and filtered. The
filtrate was concentrated at reduced pressure and dried in vacuum.
To the resulting product was added 500 ml of dehydrated
dichloromethane (reagent, Kanto Kagaku Co., Ltd.) and cooled to
-25.degree. C. The mixture was filtered, concentrated and dried in
vacuum. The residue was purified through alumina column (ICN
Biomedicals. GmbH, ICN Alumina N, Act.1/eluent acetonitrile). The
eluate was concentrated and dried in vacuum to obtain 56.2 g of the
desired product (colorless liquid). The product was checked for
.sup.1H-NMR, electrical conductivity and voltage resistance as in
Example 1.
[0146] .sup.1H-NMR(CD.sub.3OD) .delta.ppm:
[0147] 2.20(m 4H), 3.09(s 3H), 3.45(m 2H), 3.58(m 2H), 3.66(s 3H),
4.61(s 2H)
[0148] electrical conductivity: 5.96 mS/cm(25.degree. C.)
[0149] voltage resistance: 4.2V
Example 4
Preparation of N-methoxymethyl-N-methylpyrrolidinium isocyanate
[0150] In 325 g of water was dissolved 55.5 g of
N-methoxymethyl-N-methylpyrrolidinium chloride and thereto was
added 51.0 g of silver cyanate(reagent, Aldrich Corp.). The mixture
was reacted at room temperature for 9 hours, cooled to 5.degree. C.
and filtered. The filtrate was concentrated at reduced pressure and
dried in vacuum. To the resulting product was added 5000 ml of
dehydrated ethanol (reagent, Kanto Kagaku Co., Ltd.) and cooled to
-25.degree. C. The mixture was filtered, concentrated and dried in
vacuum. The residue was purified through alumina column (ICN
Biomedicals. GmbH, ICN Alumina N, Act.1/eluent acetonitrile). The
eluate was concentrated and dried in vacuum to obtain 43.6 g of the
desired product (colorless liquid). The product was checked for
.sup.1H-NMR, electrical conductivity and voltage resistance as in
Example 1.
[0151] .sup.1H-NMR(CD.sub.3OD) .delta.ppm:
[0152] 2.21(m 4H), 3.09(s 3H), 3.45(m 2H), 3.58(m 2H), 3.66(s 3H),
4.60(s 2H)
[0153] electrical conductivity: 5.81 mS/cm(25.degree. C.)
[0154] voltage resistance: 3.3V
Example 5
Preparation of N-methoxymethyl-N-methylpyrrolidinium nitrite
[0155] In 162.3 g of water was dissolved 48.2 g of
N-methoxymethyl-N-methylpyrrolidinium chloride and thereto was
added 50.7 g of silver nitrite (reagent, Aldrich Corp.). The
mixture was reacted at room temperature for 12 hours and at
50.degree. C. for 8 hours, cooled to 5.degree. C. and filtered. The
filtrate was concentrated at reduced pressure and dried in vacuum.
To the resulting product was added 5000 ml of dehydrated ethanol
(reagent, Kanto Kagaku Co., Ltd.) and cooled to -25.degree. C. The
mixture was filtered, concentrated and dried in vacuum. The residue
was purified through alumina column (ICN Biomedicals. GmbH, ICN
Alumina N, Act.1/eluent ethanol). The eluate was concentrated and
dried in vacuum to obtain 43.8 g of the desired product (colorless
liquid). The product was checked for .sup.1H-NMR and electrical
conductivity as in Example 1.
[0156] .sup.1H-NMR(CD.sub.3OD) .delta.ppm:
[0157] 2.19(m 4H), 3.08(s 3H), 3.44(m 2H), 3.56(m 2H), 3.65(s 3H),
4.59(s 2H)
[0158] electrical conductivity: 4.83 mS/cm(25.degree. C.)
Example 6
Preparation of N-ethyl-N-methoxymethylpyrrolidinium thiocyanate
[0159] In 140 g of ethanol was dissolved 27.1 g of sodium
thiocyanate (reagent, Wako Pure Chemical Ind. Ltd.). In 20.0 g of
ethanol was dissolved 40.0 g of
N-ethyl-N-methoxymethylpyrrolidinium chloride. The latter solution
was added dropwise to the former solution at room temperature over
a period of 0.5 hour to perform salt exchange. The mixture was
stirred at room temperature for 36 hours to complete the reaction
and filtered. The resulting solid product was washed with 300 g of
ethanol. The filtrate was dried at reduced pressure. To the
resulting product was added 200 ml of dehydrated chloroform
(reagent, Wako Pure Chemical Ind. Ltd.) and cooled to -25.degree.
C. The mixture was filtered, concentrated and dried in vacuum. The
residue was purified through alumina column (ICN Biomedicals. GmbH,
ICN Alumina N, Act.1/eluent acetonitrile). The eluate was
concentrated and dried in vacuum to obtain 39.9 g of the desired
product (colorless liquid). The product was checked for .sup.1H-NMR
and electrical conductivity as in Example 1.
[0160] .sup.1H-NMR (CDCl.sub.3) .delta.ppm:
[0161] 1.45(t 3H), 2.33(m 4H), 3.61(m 4H), 3.71(s 3H), 3.80(m 2H),
4.78(s 2H)
[0162] electrical conductivity: 8.8 mS/cm(25.degree. C.)
Example 7
Preparation of N-ethoxymethyl-N-methylpyrrolidinium dicyanamide
[0163] In 200.0 g of water was dissolved 42.8 g of
N-ethoxymethyl-N-methylpyrrolidinium chloride and thereto was added
44.6 g of silver dicyanamide. The mixture was reacted at 50.degree.
C. for 34 hours, cooled to room temperature and filtered. The
filtrate was concentrated at reduced pressure and dried in vacuum.
To the resulting product was added 500 ml of dehydrated
dichloromethane (reagent, Kanto Kagaku Co., Ltd.) and cooled to
-25.degree. C. The mixture was filtered, concentrated and dried in
vacuum. The residue was purified through alumina column (ICN
Biomedicals. GmbH, ICN Alumina N. Act.1/eluent acetonitrile). The
eluate was concentrated and dried in vacuum to obtain 45.4 g of the
desired product (colorless liquid). The product was checked for
.sup.1H-NMR and electrical conductivity.
[0164] .sup.1H-NMR(CDCl.sub.3) .delta.ppm:
[0165] 1.33(t 3H), 2.31(m 4H), 3.20(s 3H), 3.53(m 2H), 3.70(m 2H),
3.91(q 2H), 4.73(s 2H)
[0166] electrical conductivity: 15.8 mS/cm (25.degree. C.)
Example 8
[0167] The N-methoxymethyl-N-methylpyrrolidinium dicyanamide
prepared in Example 1 and propylene carbonate were mixed together
within a dry box having a nitrogen atmosphere, up to -60.degree. C.
in dew point, to obtain solutions having varying concentrations.
The solutions prepared were checked for water content by a Karl
Fischer moisture meter (Hiranuma Moisture Meter AQ-7, product of
Hiranuma Sangyo Co., Ltd.) and found to be up to 30 ppm in water
content. Table 1 shows the concentrations of the solutions. The
solutions were checked for electrical conductivity.
<Observation of State of Compositions>
[0168] The above compositions were each placed into glass
containers having a screw plug inside the dry box, in an amount of
4 cc in each container and brought out of the dry box. The glass
containers containing the composition were immersed in a
constant-temperature bath and held at 25.degree. C., 0.degree. C.
or -30.degree. C. for 5 hours and checked for state visually. The
results are shown in Tables, in which "-" indicates separation into
two layers, and "solid" represents a solid state.
<Measurement of Electrical Conductivity>
[0169] The solution compositions which were found to be in a liquid
state free of separation or solidification were brought out of the
dry box and checked for electrical conductivity using a
conductivity meter (CDM210, product of Radiometer Analytical SAS).
The measuring cell used was XE-100 (product of Radiometer
Analytical SAS).
TABLE-US-00001 TABLE 1 electrical conductivity electrolyte PC
(25.degree. C.) (0.degree. C.) (-30.degree. C.) (wt %) (wt %)
(mS/cm) (mS/cm) (mS/cm) Ex. 8 20 80 17.2 10.8 4.5 30 70 20.4 12.7
4.9 40 60 22.6 13.4 4.9 60 40 23.4 13.2 4.5 80 20 22.8 12.3 4.2 100
0 21.6 10.2 2.7
Example 9
[0170] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-methoxymethyl-N-methylpyrrolidinium dicyanamide prepared in
Example 1 and acetonitrile.
TABLE-US-00002 TABLE 2 electrical conductivity electrolyte AN
(25.degree. C.) (0.degree. C.) (-30.degree. C.) (wt %) (wt %)
(mS/cm) (mS/cm) (mS/cm) Ex. 9 20 80 50.4 44.3 29.6 40 60 68.8 51.4
32.9 50 50 70.0 53.5 32.1 60 40 67.2 49.4 27.4 80 20 48.1 30.3 14.1
100 0 21.6 10.2 2.7
Example 10
[0171] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-methoxymethyl-N-methylpyrrolidinium thiocyanate prepared in
Example 2 and propylene carbonate.
TABLE-US-00003 TABLE 3 electrical conductivity electrolyte PC
(25.degree. C.) (0.degree. C.) (-30.degree. C.) (wt %) (wt %)
(mS/cm) (mS/cm) (mS/cm) Ex. 10 20 80 15.3 9.4 3.4 40 60 19.3 10.7
3.3 60 40 19.1 9.9 2.9 80 20 17.0 8.1 2.1 100 0 14.1 6.4 1.5
Example 11
[0172] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-methoxymethyl-N-methylpyrrolidinium thiocyanate prepared in
Example 2 and acetonitrile.
TABLE-US-00004 TABLE 4 electrical conductivity electrolyte AN
(25.degree. C.) (0.degree. C.) (-30.degree. C.) (wt %) (wt %)
(mS/cm) (mS/cm) (mS/cm) Ex. 11 20 80 43.4 35.4 23.6 40 60 60.0 45.4
27.9 50 50 60.9 44.8 25.4 60 40 58.2 40.1 21.5 80 20 40.5 23.7 8.7
100 0 14.1 6.4 1.5
Example 12
[0173] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-methoxymethyl-N-methylpyrrolidinium nitrate prepared in Example 3
and propylene carbonate.
TABLE-US-00005 TABLE 5 electrolyte PC electrical conductivity (wt
%) (wt %) (25.degree. C.) (mS/cm) Ex. 12 20 80 12.0 40 60 13.7 60
40 12.1 80 20 9.1 100 0 6.0
Example 13
[0174] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-methoxymethyl-N-methylpyrrolidinium nitrate prepared in Example 3
and acetonitrile.
TABLE-US-00006 TABLE 6 electrolyte AN electrical conductivity (wt
%) (wt %) (25.degree. C.) (mS/cm) Ex. 13 20 80 35.7 40 60 46.6 60
40 44.5 80 20 27.9 100 0 6.0
Example 14
[0175] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-ethyl-N-methoxymethylpyrrolidinium thiocyanate prepared in
Example 6 and acetonitrile.
TABLE-US-00007 TABLE 7 electrical conductivity electrolyte AN
(25.degree. C.) (-30.degree. C.) (wt %) (wt %) (mS/cm) (mS/cm) Ex.
14 20 80 39.6 19.4 40 60 52.3 20.9 60 40 50.5 15.3 80 20 32.4 5.3
100 0 8.8 solid
Example 15
[0176] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using
N-ethoxymethyl-N-methylpyrrolidinium dicyanamide prepared in
Example 7 and acetonitrile.
TABLE-US-00008 TABLE 8 electrical conductivity electrolyte AN
(25.degree. C.) (-30.degree. C.) (wt %) (wt %) (mS/cm) (mS/cm) Ex.
15 20 80 45.3 22.0 40 60 59.1 23.7 60 40 55.6 17.4 80 20 39.2 8.5
100 0 15.8 1.5
Comparative Example 1
Preparation of N-methoxyethyl-N-methylpyrrolidinium
tetrafluoroborate
[0177] N-methylpyrrolidine (31.10 g, reagent, product of Tokyo
Kasei Co., Ltd.) was dissolved in 124.30 g of toluene, followed by
replacement with nitrogen. To the solution was added dropwise 61.22
g of bromoethyl methyl ether (reagent, product of Aldrich Corp.) at
27.degree. C. over a period of 1 hour. The mixture was heated to a
gradually raised temperature and then stirred at 60 to 70.degree.
C. for 37 hours to terminate the reaction. The reaction mixture was
cooled to room temperature, and the resulting solids were filtered
off under a nitrogen stream. The filter cake was washed with 70 g
of toluene and thereafter dried in a vacuum (giving 78.99 g of a
brown solid product). The solid product obtained was suspended in
200 g of acetone, and the suspension was stirred at room
temperature, followed by washing with stirring at room temperature
and filtration under a nitrogen stream. (This procedure was
repeated twice.) The product was dried in a vacuum to result in a
yield of 62.64 g. The product, which was colored, was dissolved in
131.83 g of water, 6.00 g of activated carbon (Carboraffin, product
of Takeda Pharmaceutical Co., Ltd.) was added to the solution, and
the mixture was stirred at 90 to 95.degree. C. for 12 hours. The
mixture was cooled to room temperature, and the activated carbon
was separated off by filtration. The filtrate was concentrated in a
vacuum, followed by drying in a vacuum to result in a yield of
58.34 g. The product was dissolved in a solvent mixture of 200.48 g
of acetone and 27.22 g of chloroform with heating for
recrystallization. The resulting white solids obtained were
filtered off in a nitrogen stream, washed with 50 g of acetone and
dried in a vacuum, giving 34.10 g of
N-methoxyethyl-N-methylpyrrolidinium bromide.
[0178] .sup.1H-NMR (CD.sub.3OD) .delta.ppm: 2.24(m 4H), 3.15 (s
3H), 3.40(s 3H), 3.65(m 6H), 3.83(m 2H)
[0179] Subsequently, 40.0 g of the
N-methoxyethyl-N-methylpyrrolidinium bromide prepared was dissolved
in 40.0 g of MeOH, and 54.0 g of methanol solution of 30 wt. %
HBF.sub.4 was added to the solution. The mixture was heated at
130.degree. C. in a nitrogen stream to remove hydrogen chloride
produced as a by-product and an excess of HBF.sub.4, giving 39.9 g
of the desired product (white solid).
[0180] .sup.1H-NMR (CD.sub.3OD) .delta.ppm: 2.22(m 4H), 3.10 (S
3H), 3.39 (S 3H), 3.58(m 6H), 3.81(m 2H)
[0181] The solutions were checked for electrical conductivity in
the same manner as in Example 8 with the exception of using the
above N-methoxyethyl-N-methylpyrrolidinium tetrafluoroborate and
propylene carbonate.
TABLE-US-00009 TABLE 9 electrolyte PC electrical conductivity (wt
%) (wt %) (25.degree. C.) (mS/cm) Com. Ex. 1 20 80 12.2 40 60 13.0
60 40 10.1 80 20 6.3 100 0 2.8
INDUSTRIAL APPLICABILITY
[0182] A quaternary ammonium salt of the formula (1), and an
electrolytic solution containing the salt of the present invention
are highly soluble in organic solvents, highly reliable at low
temperatures and highly electrically conductive, and are suitable
for an electrolyte for electrochemical devices. Further, these
quaternary ammonium salts are free of halogen and an electrolytic
solution can be obtained which is less likely to burden the
environment.
* * * * *